Betelgeuse -- A Century and more of Variation

TL;DR

This paper analyzes over a century of observational data of Betelgeuse, revealing its long-term variability, persistent ~400-day feature, and historical brightness changes, highlighting its complex and active nature.

Contribution

It compiles and analyzes a century of visual data to characterize Betelgeuse's long-term variability and identifies a persistent ~400-day feature amidst complex trends.

Findings

No clear periodicity identified beyond long-term trends

A persistent feature near 400 days in the data

Betelgeuse was brighter and more active around 1836-1840

Abstract

The mean light curve of Betelgeuse is constructed from the visual data in BAA VSS and AAVSO archives. Period analysis reveals clusters of periods around 2000 and 400 days but these are swamped by the long-term trends. No identifiable periods emerge but the feature near 400 days is the most persistent and survives even when the range of variation is low. Herschel's data from 1836-40 and early data from the BAA VSS around 1900 show a range of V {\raise.3ex\hbox{\boldmath${\scriptstyle\sim}$}} 0 -- 1, so the star was brighter and more active than recently. Historically it shows a wide range of behaviour.